Traditionally, absorbent articles have included a central absorbent portion having a body facing side, a garment facing side, longitudinally extending edges and transverse ends. These articles generally include an absorbent core made of loosely associated hydrophilic materials such as wood pulp. Such products are held in place by providing patches of pressure sensitive adhesive, typically a double sided tape or a hot melt type glue, on the garment facing side that adheres it to the inner crotch surface of the wearer's undergarment.
One drawback of traditional absorbent articles has been that their shape tends to deform during use, thereby allowing the article to move out of position so as to reduce its effectiveness. Subsequent designs have addressed this problem by including tabs or wings that extend laterally from the longitudinal edges of the central portion and wrap around the edges of the undergarment. See U.S. Pat. Nos. 4,285,343 (McNair); 4,589,876 (Van Tilburg); and 4,911,701 (Mavinkurve).
One problem with using such tabbed articles arises due to the fact that the adhesive patches that attach the article to the user's undergarment are typically applied to both the tabs and the central portion. These adhesive strips are often covered with separate protective release strips that protect the adhesive from dirt and unintended adhesion during manufacture, packaging and storage. These release strips must be removed by the user just prior to application of the product to an undergarment.
Unfortunately, multiple adhesive patches and release strips make the application of the article to the undergarment a cumbersome process. Specifically, the user must remove all three release strips (one on the central portion and one on each of the tabs) while simultaneously making sure that the tabs do not inadvertently adhere to one another or to another part of the product. Thus, the user must carefully handle the product when removing the release strip on one tab in order to avoid inadvertently contacting the exposed adhesive on the other tab and the central portion, thereby rendering the product useless. Even when the problem of undesired adhesion is avoided, the user is presented with the task of disposing of three release strips.
Consequently, absorbent articles have been developed that incorporate a single, "double-sided" release strip--that is, a release strip coated on both sides with silicone or the like. The single, double-sided release strip protects the adhesive patches on both the central portion and the tabs, so that a single pull of a release strip is sufficient to prepare the article for application--see U.S. Pat No. 4,701,178 (Glaug et al.). Absorbent articles incorporating this feature are manufactured by applying pressure sensitive adhesive directly to the layers covering the garment facing sides of both the central portion and each of the tabs of the article. A double-sided release strip is then applied to the adhesive on the central body portion and the tabs are folded over the release strip so that the release strip is sandwiched between the adhesive on the central portion and the adhesive on the tabs.
Unfortunately, experience has shown that it is very difficult to apply a hot melt adhesive directly to the layers covering the garment facing side of the central portion and the garment facing sides of the tabs. The difficulty arises because the high temperature of such adhesive as it exits the glue gun can result in scorching of the material from which these layers are formed. As a result, double faced adhesive tape, although more expensive than hot melt glue, has typically been used as the tab adhesive.
Consequently, it would be desirable to provide a method of utilizing hot melt type pressure sensitive adhesive on a tabbed absorbent article, using a double sided release strip to protect the adhesive on both the tabs and the central portion of the article, in such a manner that the application of the adhesive does not result in scorching of the layers covering the article.